Lab Switch control utility
--------------------------

If invoked without arguments, labsw prints the firmware version and
build date.

The following commands can be given on the command line:

ch1=0, ch1=1, ch2=0, ch2=1
	turn the respective channel on or off. Both relay and
	opto-coupler are switched. Also enters remote mode.

query
	read the buttons and opto-coupler inputs (rear panel)

local
	exit remote mode

The Lab Switch starts in local mode, where the CH1/CH2 buttons
toggle the respective channel. The main button turns off both
channels. Local mode is indicated by a green main LED.

If a channel is set via USB, the Lab Switch enters remote mode,
indicated by a red main LED. In remote mode, the channel buttons
are ignored. Pressing the main button exits remote mode and
turns both channels off.

The lab switch utility currently lacks the following features:
- access to the rear opto-coupler outputs,
- switching CH1/CH2 relay and opto-coupler independently,
- direct control of LEDs.

Examples:

# labsw ch1=1

Turns channel 1 on and enters remote mode.

# labsw ch1=0 ch2=0 local

Turns channels 1 and 2 off and exits remote mode. This is
equivalent to pressing the main button.
